Mild steel welding fume reclassified as a human carcinogen

"Businesses need to look at the level of protection they offer"

As a result of The International Agency for Research on Cancer (IARC) releasing new scientific evidence that exposure to mild steel welding fume can cause lung cancer and possibly kidney cancer in humans, mild steel welding fume has been reclassified as a human carcinogen by the Workplace Health Expert Committee.


The Health and Safety Executive (HSE) has released a safety alert for those undertaking welding activities, including mild steel, in any industry. In order to protect workers, the HSE is strengthening its enforcement expectation for exposure control for all welding fume including mild and stainless steels, high chrome steels, armour plating and exotic metals.

3M’s Welding Expert and Application Engineer, Simon Field, looks at the changes, what they mean for UK businesses and workers, and more importantly how you can ensure you comply with them.

Prior to this new regulation there were guidelines around the risk posed by welding fumes and the types of protection that could be used and implemented. Simon explains that the level of risk posed was determined by the Health and Safety Manager in the place of work, based on the concentration of welding fumes in the working environment, the length of exposure, the type of weld fume and so on. Based on these factors, the Safety Manager then would suggest the level and methods of control required for the worker to be safe.


What are the Changes?

HSE Bulletin STSU1 – 2019:

  • All Indoor welding tasks require the use of Local Exhaust Ventilation (LEV). Respiratory Protective Equipment (RPE) is also required for any residue welding fumes.

  • Outdoor welding requires use of RPE.


What does this mean for you?

Business’ will now need to look at the level of protection they currently offer their welding workforce to ensure that it meets the expectations of the HSE. If not already in place, an RPE programme will need to be developed and implemented, ensuring workers are suitably trained and instructed in the use of this new RPE. Programmes such as this will ensure the correct RPE is selected, maintained, stored, cleaned and of course adopted and in cases where it is required that a Face-Fit Testing programme is implemented.

Also worth a mention is facial hair, explains Simon. Whilst many men in the UK love to fashion a beard, they are incompatible with some RPE solutions, in-particular those that require a tight-fitting seal. That doesn’t just mean a beard or designer stubble, workers need to be clean shaven to get a good seal with their respirator. That’s why it’s so important for the RPE selected to be correct and suitable for the workforce who will be wearing them.

The HSE has provide specific guidance on its website which outlines control measures to consider when welding in a variety of environments, in all cases when RPE is required a minimum Assigned Protection Factor (APF) of 20 is outlined.

Mary Cameron, Occupational Hygiene Team Leader at SOCOTEC, gives an overview of the changes and why control measures are fundamental to protecting employee health and safety.


Welding fume contents and risks

Welding fume is a complex and varying mixture of airborne particles, vapours and gases which arise from the thermal manipulation of metal materials. The fume particles formed from the vaporisation of molten metal as well as by-product vapours and gases may cause a wide range of adverse health effects. Welding on painted, plated, galvanised or degreased metals may cause additional inhalation exposure concerns.

Depending on the job’s specific circumstances, physical hazards should also be considered such as heat stress, EMF and noise exposure. As with any hazardous process, all aspects should be considered when undertaking the risk assessment and control measures implemented accordingly to reflect the level of risk.

What control measures do I need to implement?

It must be understood that general ventilation does not achieve the essential welding fume exposure control. Control of exposure to carcinogenic fumes requires more effective engineering controls, such as local exhaust ventilation (LEV), which allows for at-source fume extraction thus preventing welding fume from spreading into the surrounding workplace and entering the worker’s breathing zone.

Indoor welding tasks require the use of LEV. If LEV is unable to control fume capture then Respiratory Protective Equipment (RPE) is also required. Appropriate RPE should be also provided for welding outdoors. Regardless of the duration of exposure, the HSE will no longer accept any welding undertaken without suitable exposure control measures in place as there is no known level of safe exposure. Adequate exposure control measures are a necessity and for good reason.


Illness caused by welding fume exposure

Welding fume inhalation has long since been understood to be hazardous to health, even before the most recent HSE announcement classifying of mild steel welding fume as a human carcinogen.

Welders are more prone to lung infections, reduced lung function and may experience irritation of the throat and lungs. Welders may also experience flu like symptoms after welding (metal fume fever) which is usually linked to welding on galvanised metals, as well as mild steel.

Adverse health effects from exposure to manganese (present in mild steel welding fume) may include neurological effects similar to Parkinson’s disease.

Welding stainless steel can produce hexavalent chromium which is a lung carcinogen. Stainless steel fume may also contain chromium oxide and nickel oxide – both of which can cause asthma. Iron is present in most forms of welding fume and may cause siderosis which is the deposition of iron oxides in lung tissue.

This vast array of health effects is staggering and so the need for effective exposure controls is critical:

  • Suitable control measures must be applied, regardless of welding duration and including outdoors welding;

  • The employer must ensure welders are suitably instructed and trained in the use of any exposure controls (e.g. LEV, RPE);

  • All engineering controls should be correctly used, suitably maintained and subject to thorough examination and testing (if required under COSHH Regulation 9) and RPE must be subject to an RPE programme.

The recent change in enforcement expectations for control of welding fume exposure should be reflected in the risk assessment and in the current control measures on site. Control measures should be replaced or be improved upon if required as per the risk assessment and in order to reflect the reclassification of mild steel welding fume as a human carcinogen.


Ensuring compliance

Occupational hygienists identify hazardous agents (physical, chemical and biological) in the workplace that can cause occupational disease or discomfort. The aim is to evaluate the extent of the risk due to exposure and recommend the best controls to prevent ill-health. At SOCOTEC, our occupational hygienists often attend metal fabrication sites to undertake workplace exposure monitoring (including welding fume exposure) and control measure evaluations.

Occupational hygienists can help employers in their COSHH compliance programme by assessing the worker’s exposure to hazardous substances and also by undertaking examination of control measures in place to ensure continued performance or recommend improvements. Occupational hygienists are there to assess, advise and improve upon workplace hazards. SOCOTEC’s understanding in the risks involved in a wide variety of workplace activities makes us highly capable to recommend effective exposure prevention and controls measures.

Find out more about the HSE’s Safety Alert here.


IOSH urges employers to review current welding control measures.

Ensure workers are protected

The Institution of Occupational Safety and Health (IOSH) is urging employers to ensure workers are protected. Michael Edwards, IOSH’s Occupational Safety and Health Content Developer, represents the institution on the LEV committee.

He said: “The raised control standards for welding fumes are now in effect for organisations within the UK and will have implications to a whole range of different industries where welding operations occur. Further efforts must be made to protect workers involved in welding as part of their roles.

“IOSH urges employers in the UK to review current welding control measures in place to ascertain that they meet these raised control standards. This may also mean that risk assessments and risk registers may need updating to ensure that they reflect the new requirements.”


Bureau Veritas has applauded the action.

Greater scrutiny

Simon Hodge, Consultancy Group Manager at Bureau Veritas, said: “Following this reclassification there is no known level of safe exposure to welding fume and businesses can expect greater scrutiny regarding the effectiveness of engineering controls. As of now, current control methods such as general ventilation, will not be deemed acceptable. It also means that where controls are not adequate or not present – for example outside – that appropriate and effective respiratory protective equipment (RPE) is provided and used. This will include training for workers to ensure compliance.

“The HSE will also expect organisations to have up-to-date and adequate risk assessments in place which reflect the increased risk posed by this update. All employers are therefore advised to review their COSHH risk assessments for welding activities and revise where necessary their control measures to protect those undertaking welding activities. This may include introducing workplace exposure monitoring to properly assess the risk. Non-compliance will not only pose a significant safety hazard to workers but will mean that businesses leave themselves open for severe repercussions from the HSE.”

When SHP first published the news, it was widely shared amongst readers and, understandably, generated a fair few questions. We put your questions to the HSE:

Does the enforcement apply to just welding or mild steel cutting as well?

“The specific change in enforcement expectation approved by the Regulatory Committee applies to welding processes which is what the IARC research addresses; however, the fumes produced during the cutting process are likely to be very similar to those during welding, and in some situations at a higher volume. Therefore, duty holders will need to assess the risk of what is being produced and control exposure as required.

“HSE’s Construction Division is producing a briefing which will state: Prior to the change, duty holders would have had to assess the risk and put in appropriate controls depending on what they were cutting up and how coated it was with contaminants. However, the expectation in relation to these controls and any enforcement action has increased in line with that for mild steel – effectively from the same date.”


What is the HSE doing to enforce it?

“Inspectors will be discussing the control of exposure to welding fume during any Inspections where they find it occurs with immediate effect and there will be a specific Inspection Campaign for fabricated metal premises in Q4 where this topic will be addressed specifically.”


How can workers ensure they are working with an acceptable amount of ventilation?

“The requirement is for use of suitable local exhaust ventilation where reasonably practicable to do so, this should look to remove (ideally) all fume, where there is obvious visual residual fume further controls will be required in the form of RPE.”


Should employers now review their COSHH risk assessment?

“Yes, if they are welding mild steel and did not have any exposure controls in place previously, to ensure they provide suitable control measures going forwards.”


How you can prove who is at fault if you do suffer from exposure?

“This question is a matter of civil law; an individual would need to take legal advice form a personal injury lawyer. HSE attention would be on the criminal law and whether the individual’s current employer has and is currently managing the risk.”


People are dismissive of more legislation. Welding is about to become cumbersome. We already use the best extraction. Is that going to be enough?

“This isn’t new legislation, but it is a response to the IARC research on cancer risk when welding. There have always been requirements for control of exposure in place for a number of other metals such as stainless steel, galvanised steel, exotic metals, so this shouldn’t come as a big change for those organisations that already weld some of these types; this may be a big change for those only welding mild steel. If the extraction system currently in place is removing all visible fume at source, then they should not need any further controls.”